The Mini is great for its form factor, but lacking in display compared to the Air as a drawback in size. I've yet to get my hands on the Mini Retina, but I'd favor the smaller form factor a little more. Both devices are spectacular by all accounts. If you like the larger screen as such on your current 3, I'd recommend getting the Air as its lighter and faster. If you feel that you'd like a change of size, I'd say play around with one first before committing. Best way to testdrive and compare would be at an Apple store or a carrier that has both the Mini Retina and the Air side by side for comparison
Sent from my iPad Mini via Tapa